Furnace safety valve and system

ABSTRACT

A system for automatically shutting off gas flow to a furnace may include an inlet for supplying a gas to the furnace. The furnace may have a housing. The system may include a thermometer positioned inside between the furnace and the housing. A resettable limit switch may be in electrical communication with the thermometer. An electric shutoff valve may be positioned inline between the inlet and the furnace and in electrical communication with the resettable limit switch. A manual shutoff valve may be positioned inline between the inlet and the electric shutoff valve and may manually shut off gas flow to the furnace. When the thermometer reaches a predetermined temperature, the resettable limit switch may actuate the electric shutoff valve thereby shutting off flow of the gas to the furnace. The electric shutoff valve may only be re-opened by manually resetting the resettable limit switch.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority of U.S. Provisional Application No. 62/724,990, filed on Aug. 30, 2018, and is hereby incorporated by reference in the entirety.

TECHNICAL FIELD AND BACKGROUND OF THE INVENTION

The invention relates generally to the field of gas safety and more particularly to the safety devices for appliances. The present invention is a furnace safety valve arranged to turn off gas supply to a furnace in the event of a fire.

Furnaces are appliances used to supply heat to homes and other structures. Furnaces may also be used to supply heated water and for other applications. While some furnaces run purely off of electricity, solar, or geothermal power, many furnaces utilize hydrocarbon fuel, either alone or in combination with another source. Such hydrocarbons include natural gas, liquid petroleum gas, petroleum, methane, kerosene, diesel, oil, and other hydrocarbons. In this application, unless otherwise stated, the term “gas” will refer to any one or more of these hydrocarbons used to fuel a furnace.

Furnaces typically have gas supplied either by a municipal connection, by a local tank, or by a well. The gas is fed into the furnace, consumed, and the heat is supplied to the building structure. Unfortunately, because a furnace causes the gas to combust, it is not uncommon for the furnace to malfunction and cause a fire. For instance, the furnace may, over time, rust or deteriorate leading to a fire. Gas lines inside the furnace may leak and exacerbate the fire. Worse, the gas inlet continues to supply fuel to the fire as the conflagration expands. When this happens, the structure and adjacent structures may burn to the ground. Accordingly, there is a need in the art for a device and system to abate the potential for furnace fires.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a device that prevents furnace fires. It is another object of the invention to provide a system which may be automatically deployed and which may be reset only by a manual action of a person.

It is a still further object of the invention to provide a device and system which may be economically manufactured and is able to be installed in a retrofit installation on existing furnaces.

These and other objects and advantages of the invention are achieved by providing a system for automatically shutting off gas flow to a furnace. The system has an inlet for supplying a gas to the furnace, a housing surrounding the furnace for insulating the furnace, a thermometer positioned inside between the furnace and the housing, a resettable limit switch in electrical communication with the thermometer, an electric shutoff valve positioned inline between the inlet and the furnace and in electrical communication with the resettable limit switch, and a manual shutoff valve, positioned inline between the inlet and the electric shutoff valve, for manually shutting off gas flow to the furnace. As configured once thermometer reaches a predetermined temperature, the resettable limit switch actuates the electric shutoff valve thereby shutting off flow of the gas to the furnace. The electric shutoff valve may only be re-opened by manually resetting the resettable limit switch.

According to another embodiment of the invention the electric shutoff valve is powered by a battery.

According to another embodiment of the invention the electric shutoff valve is powered by an electrical connection to the furnace.

According to another embodiment of the invention, the gas is selected from a group consisting of natural gas, liquid petroleum gas, petroleum, methane, kerosene, diesel, or oil.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is best understood when the following detailed description of the invention is read with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of the invention;

FIG. 2 is a perspective view of the invention;

FIG. 3 is a schematic view of the invention; and

FIG. 4 is a front view of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1, FIG. 2, FIG. 3, and FIG. 4. A gas fired furnace 42 may have a housing 40 which surrounds the furnace. The housing 40 may provide insulation and protection to the furnace. A gas inlet 20 may supply gas to the furnace. A manual shutoff valve 22 may be positioned inline between inlet 20 and the furnace 42.

A thermometer 36 may be positioned between the housing 40 and the furnace 42. The thermometer 36 may be in communication via a wire 32 with a resettable limit switch 34. The resettable limit switch 34 may be in communication with an electric gas shutoff valve 30 via a wire 38. The electric gas shutoff valve 30 may be positioned in line between inlet 20 and the furnace 42.

As shown, the manual shutoff valve 22 may be positioned between the electric shutoff valve 30 and the inlet 20. Gas may flow from the gas inlet 20 to the manual shutoff valve 22 and then through a first gas conduit 24 to the electric shutoff valve 30. Gas may then flow from the electric shutoff valve 30 through a second gas conduit 26 and finally into the furnace 42.

The resettable limit switch 34 is configured such that, when the thermometer 36 reaches a predetermined temperature the resettable limit switch 34 actuates the electric shutoff valve 30 thereby shutting off gas flow to the furnace 42. The gas flow to the furnace 42 may only again return when the electric shutoff valve 30 is reopened. The electric shutoff valve 30 may only be reopened when a person manually resets the resettable limit switch. 

What is claimed is:
 1. A system for automatically shutting off gas flow to a furnace comprising: an inlet for supplying a gas to the furnace; a housing surrounding the furnace for insulating the furnace; a thermometer positioned inside between the furnace and the housing; a resettable limit switch in electrical communication with the thermometer; an electric shutoff valve positioned inline between the inlet and the furnace and in electrical communication with the resettable limit switch; and a manual shutoff valve, positioned inline between the inlet and the electric shutoff valve, for manually shutting off gas flow to the furnace; wherein, when the thermometer reaches a predetermined temperature, the resettable limit switch actuates the electric shutoff valve thereby shutting off flow of the gas to the furnace; and wherein, the electric shutoff valve may only be re-opened by manually resetting the resettable limit switch.
 2. The system of claim 1 wherein the electric shutoff valve is powered by a battery.
 3. The system of claim 1 wherein the electric shutoff valve is powered by an electrical connection to the furnace.
 4. The system of claim 1 wherein the gas is selected from a group consisting of natural gas, liquid petroleum gas, petroleum, methane, kerosene, diesel, or oil.
 5. A system for automatically shutting off gas flow to a furnace comprising: a thermometer positioned inside a housing surrounding the furnace; a resettable limit switch in electrical communication with the thermometer; an electric shutoff valve in electrical communication with the resettable limit switch and positioned inline between the furnace and a gas inlet; wherein, when the thermometer reaches a predetermined temperature, the resettable limit switch actuates the electric shutoff valve thereby shutting off flow of the gas to the furnace; and wherein, the electric shutoff valve may only be re-opened by manually resetting the resettable limit switch.
 6. The system of claim 5 further comprising a manual shutoff valve positioned between the inlet and the electric shutoff valve.
 7. The system of claim 5 wherein the electric shutoff valve is powered by a battery.
 8. The system of claim 5 wherein the electric shutoff valve is powered by an electrical connection to the furnace.
 9. The system of claim 8 wherein the gas is selected from a group consisting of natural gas, liquid petroleum gas, petroleum, methane, kerosene, diesel, or oil.
 10. The system of claim 5 wherein the resettable limit switch actuates the electric shutoff valve at temperatures at or above the predetermined temperature.
 11. The system of claim 5 wherein the resettable limit switch actuates the electric shutoff valve at temperatures at or below the predetermined temperature.
 12. The system of claim 5 wherein the resettable limit switch is positioned outside of the housing.
 13. The system of claim 12 wherein the resettable limit switch is attached to an outside surface of the housing.
 14. The system of claim 5 wherein the resettable limit switch is positioned inside of the housing.
 15. A method for automatically shutting off and manually re-opening gas flow to a furnace, the method comprising: measuring temperature with a thermometer positioned inside a housing surrounding the furnace; detecting a predetermined temperature by a resettable limit switch in electrical communication with the thermometer; shutting off gas flow to the furnace, when the predetermined temperature is detected, by closing an electric shut off valve in electrical communication with the resettable limit switch; and re-opening gas flow to the furnace only when the resettable limit switch is manually reset.
 16. The method of claim 15 wherein the electric shutoff valve is powered by a battery.
 17. The method of claim 15 wherein the electric shutoff valve is powered by an electrical connection to the furnace.
 18. The method of claim 15 wherein the gas is selected from a group consisting of natural gas, liquid petroleum gas, petroleum, methane, kerosene, diesel, or oil. 